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12-01-2008, 02:46 AM   #16
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one thing for me that has improved focus times is to learn to put the focus spot on an area where there is high contrast like on an eyebrow or the line between a person hair and face. In the past I would focus on someone's cheek or forehead and there really isn't a whole lot of contrast there which makes the camera's job much harder. And to second what others have said... the 50 1.4 is not a fast focusing lens, but it is a fast aperture lens (there is a big distinction there). I've been using the 360 flash a bit more lately and have found the focus assist beam on it a real help. If you need a relatively fast focusing zoom for not much money, try the sigma 24-60... around 200 on amazon, has a 2.8 aperture throughout the range, and it focuses faster than the kit lens or the 50 1.4.

12-01-2008, 11:05 PM   #17
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It also depends a lot on the lens. I've compared the K10D with the FA50 to a D80 with the 18-135 lens, and the Pentax focused considerably faster and hunted a lot less in low light.
12-02-2008, 02:58 AM   #18
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The thing is, when I'm doing portrait shots with the 1.4/50mm, it can't focus fast enough for me to catch the right facial expression. I think that is the biggest con that I've experienced, and that alone make me think of switching to Canon/Nikon. But besides that, shooting static objects and landscapes have been all good and well.

I just received three MF lens in the mail:

2/50mm (makes me wonder why I need my 1.4/50mm )
3.5/50mm? (this one is small!)
Jupiter 9 (the infamous)



Still waiting on my M42 adapters...after that, it's time to learn how to use 'em!
12-02-2008, 08:37 AM   #19
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QuoteOriginally posted by systemA Quote
The thing is, when I'm doing portrait shots with the 1.4/50mm, it can't focus fast enough for me to catch the right facial expression. I think that is the biggest con that I've experienced, and that alone make me think of switching to Canon/Nikon. But besides that, shooting static objects and landscapes have been all good and well.

I just received three MF lens in the mail:

2/50mm (makes me wonder why I need my 1.4/50mm )
You probably know a lot more about portraiture than me -

however your last statement about the MF lens probably says it well....

How would anyone ever stand a chance of taking any fleeting expression before AF with a Manual Focus lens?

Ah, easy right?
- one focusses the lens manually beforehand, and merely wait for the expression -
then it is simply tripping the shutter -
then the delay/lag is in the ballpark of <0.1sec.

One can similarly do the same thing with an AF lens -
pre-Focus the lens by a gentle half depression of the shutter button and hold that pre-Focus
and wait for the expression and then fully depress the shutter
to get <0.1 sec delay/lag -
which is about 3-5x faster than even the fastest AF from any manufacturer.....


Last edited by UnknownVT; 12-02-2008 at 12:22 PM. Reason: typo
12-02-2008, 08:49 AM   #20
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im pretty sure those guys and gals in the studio with their hasselblads aren't auto focusing.
12-02-2008, 08:55 AM   #21
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QuoteOriginally posted by systemA Quote
The thing is, when I'm doing portrait shots with the 1.4/50mm, it can't focus fast enough for me to catch the right facial expression.
If you're shooting portraits, there's absolutely no reason to wait for the expression to focus. Get the focus first, then wait for the expression, then take the picture. Lots of ways to accomplish this - either half-press and hold the shutter to focus and then wait, or configure the AF or OK button to temporarily cancel AF or use the same button to *enable* AF, or switch to MF after focusing.
12-02-2008, 10:16 AM   #22
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I took some shots at my grandmothers 89th bday, and was using a k10d w/ the tamron 28-75 and the 360 flash or a different k10d and the pentax 43mm w/ no flash and it was working great. quick snappy focus as long as I was prefocusing to the general area where the subjects were and I was focusing on a high contrast area... no problem w/ hitting the right expressions so long as I kept the cam to my face (after all, if you have the cam down, by the time you see the expression you want, raise your cam, and get things composed, the shot is likely to be gone). Granted, I have improved on my technique over the last few family events and I'm getting more keepers. It took time to learn, but I'm very glad I'm getting better at it and I'm very happy w/ the system I'm using. Really, I feel as though I'm still the weak link, not the camera!


Anyways, here's some samples...

my uncle teasing my grandmother

Camera: Pentax K10D
Exposure: 0.017 sec (1/60)
Aperture: f/5.6
Focal Length: 55 mm
ISO Speed: 640
Exposure Bias: 0/10 EV
Flash: Flash fired


my nephew pointing at her dad from the balcony

Camera: Pentax K10D
Exposure: 0.017 sec (1/60)
Aperture: f/5.6
Focal Length: 75 mm
ISO Speed: 640
Exposure Bias: 0/10 EV
Flash: Flash fired


the mother of my nephew (far left) looking scared that her daughter is about to stick her finger in the cake

Camera: Pentax K10D
Exposure: 0.017 sec (1/60)
Aperture: f/5.6
Focal Length: 75 mm
ISO Speed: 640
Exposure Bias: 0/10 EV
Flash: Flash fired


my nephew looking like she sees an opportunity to have some fun

Camera: Pentax K10D
Exposure: 0.033 sec (1/30)
Aperture: f/2.5
Focal Length: 43 mm
ISO Speed: 800
Exposure Bias: 0/10 EV
Flash: Flash did not fire


playing w/ the pink lawnmower

Camera: Pentax K10D
Exposure: 0.02 sec (1/50)
Aperture: f/2.5
Focal Length: 43 mm
ISO Speed: 500
Exposure Bias: 0/10 EV
Flash: Flash did not fire
12-02-2008, 10:57 PM   #23
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Battery Voltage

QuoteOriginally posted by cpopham Quote
I can't speak for Eneloops - I used to use Energizer 2500 mAh rechargables. What I do know is this - the very best NiMH battery is 1.2V, and Lithium AAs are 1.5V. When you add this up in a full set of batteries, it's quite a lot less voltage...

As far as Lithium AAs go, I've found Energizer e2 Ultimate batteries work pretty well.

One thing to consider if you're trying to compare the AF on two cameras - make sure you're testing at around the same depth of field. The FA 50, for example, will have a very narrow DOF, compared to, for example, a normal kit type zoom at f3.5, or f4.5 - this means that while the camera has more light available to focus, it also has to focus more precisely.
I use a very smart charger from La Crosse Technology (La Crosse, China, apparently) and it tells me that my NiMH Energizers and Eneloops charge up to about 1.4V. By 1.2V they're so far down that they're hard to charge. They spend most of their time between 1.38 and 1.28V. I use these in my flash and my Canon A720.

If I'm looking for top performance from the Canon I use lithium cells. It seems to help the Canon's notoriously slow recharge time using the flash.

I've also noticed that the rechargeables fail quickly with a Radio Shack scanner I use. Just not enough voltage except when freshly charged.

On another track, I've just acquired a Sigma 18-50mm 2.8 and found that focus improved significantly over the Sigma 17-70 2.8/4.5 or Tamron 18-250 3.5/6.3. The Sigma 2.8 now focuses faster with and without the Metz assist lamp.

In fact, it can get a focus when I wasn't able to get one at all with the other lenses. Up to that point, I was ready to send the K10D in for inspection or change to another system. Either of those choices was cheaper than throwing the K10D out the window.

12-03-2008, 12:16 AM   #24
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QuoteOriginally posted by glanglois Quote
I use a very smart charger from La Crosse Technology (La Crosse, China, apparently) and it tells me that my NiMH Energizers and Eneloops charge up to about 1.4V.
Yes, indeed, for a very small part of the discharge cycle the voltage is above 1.2V. Unfortunately, the camera applies a fairly substantial loading, and so the voltage drops very rapidly to close to 1.2V. According to Energizer themselves, the nominal voltage of the battery is 1.2V

Here is the datasheet (pdf) for the Energizer 2500mAh NiMH Rechargable.

To contrast, here is the datasheet (pdf) for the Energizer e2 Lithium AA.

Here's the Eneloop datasheet (pdf), in case you were wondering
12-03-2008, 01:24 AM   #25
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QuoteOriginally posted by glanglois Quote
my NiMH Energizers and Eneloops charge up to about 1.4V. By 1.2V they're so far down that they're hard to charge. They spend most of their time between 1.38 and 1.28V.
Open circuit voltages (ie: with no load) would be about the same for Energizer 2500mAh NiMH and eneloops - because they are both basically NiMH batteries.

However under load - like being used - their behavior can be significantly different for voltage sensitive devices - like Pentax dSLRs (that use AA batteries)

For example the K100D would shutdown when the voltage drops below 1.19V each (= 4x 1.19V = 4.76V) - eneloops manage to maintain voltage level better than the Energizer 2500mAh -

I am borrowing SilverFox's excellent discharge graph of the Energizer 2500mAh NiMH


If we look first at the 2Amp discharge curve (dark green) we can see that after about 0.4Amp-hours (on the horizontal axis) the curve has dropped to abut 1.19V - the cut-off voltage of the Pentax K100D -

So if the K100D drew 2Amp constant current (which it doesn't) - then at 0.4Amp-hours which would be about 0.2 hours or 12 minutes the K100D would shutdown because the batteries would not be able to deliver enough current at the required voltage - or saying the same thing another way for the required current of 2Amps the batteries are no longer able to maintain a voltage above 1.19V - both are saying the same thing - but to be strict - it is the battery unable to deliver the required power - watts......

Now look at the 1Amp curve (mauve/burgundy) it manages to stay above 1.19V until about 1.6Amp-hours - at 1Amp this would be about 1.6hours.

So at a lower 1Amp draw the batteries would last about 1.6hours (if it was contant current - again this is not really the case - but just a mere example) -

At the lower current of 1Amp one can see the K100D could utilize more of the battery's charge of about 1.6Ah out of a tested total 2.230Ah - whereas at 2Amps only about 0.4Ah is utilized out of the tested total of 2.236Ah.

Now let's look at the eneloop - discharge graph again borrowed from SilverFox -


Using the same 2Amp draw curve (dark green) one sees for the eneloop - the curve does not dip to 1.19V until about 1.4Ah.
And for 1Amp (mauve/burgundy) the curve stays above 1.19V until about 1.7Ah.

So the eneloop manages 1.4Ah out of a tested total of 1.807Ah at 2Amps,
and 1.7Ah out of a tested total of 1.871Ah at 1Amp......

The respective total energy tested were -

Energizer 2500mAh NiMH
2.555Wh at 2Amps
2.674Wh at 1Amp

Eneloop
2.158Wh at 2Amps
2.320Wh at 1Amp

clearly the Energizer 2500mAh NiMH hold more charge/energy than the eneloop -

Yet the eneloop would be able to deliver more of its charge/energy than the Energizer.

Last edited by UnknownVT; 12-03-2008 at 11:40 AM. Reason: typo
12-03-2008, 02:09 AM   #26
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To above: Very interesting! I wasn't aware that the shutdown coorelates to the voltage drop to 1.9v, but it sure makes sense. My eneloops lasted ~800 shots with a bit of previewing, which I found to be very impressive and was really unwilling to give it up.

However, I took the dive and purchased a k10d. Shake Reduction should definitely help, and hopefully the faster AF will be better, if not substantial for my uses. Hopefully the battery will last a good while. On the subject, are there any 3rd party batteries for the k10d you guys recommend? I was considering a battery grip, but I have small hands and prefer the smaller size and weight. But yeah, if anyone wants a good deal on a Samsung *ist DL, do give me a PM

Thanks to everyone for the tips on manual portrait shooting, I think I'll get a better feel for it when I actually go ahead and use MF. I think getting to that point is the real pusher.

Last edited by systemA; 12-03-2008 at 04:33 AM.
12-03-2008, 09:43 AM   #27
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QuoteOriginally posted by systemA Quote
Thanks to everyone for the tips on manual portrait shooting
Not just manual focus - much of the advice was on using *autofocus*, but doing the autofocus operation before you actually take the shot (using shutter half-press, or OK/AF button). No use of manual focus anywhere in the process (although MF is certainly an option too).
12-03-2008, 03:39 PM   #28
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QuoteOriginally posted by Marc Sabatella Quote
Not just manual focus - much of the advice was on using *autofocus*, but doing the autofocus operation before you actually take the shot (using shutter half-press, or OK/AF button). No use of manual focus anywhere in the process (although MF is certainly an option too).
But then, after every shot, I would still need to AF...which doesn't work well for fast, continuous shots?
12-03-2008, 07:12 PM   #29
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QuoteOriginally posted by systemA Quote
But then, after every shot, I would still need to AF...
I'm not sure what you mean by this. The idea is that if you're shooting a portrait, the person presumably isn't moving. So focus once, then shoot as often as you like and don't focus again. I do this by configuring the OK button on my K200D to cancel AF (AF button on K10D/K20D can do the same) . So I half press to focus the first time, then for subsequent shots, I just put my thumb on the OK button while pressing the shutter, so it doesn't focus again. You can also do it by configuring the button to focus instead of canceling AF. That is, the shutter no longer focuses, but focus only happens when you press the OK/AF button. Or you can focus with half press then move the front switch to MF, but not actually doing any manually focusing. Lots of ways to accomplish the goal.

Of course, if the subject moves, you need to refocus, obviously. But again, no reason to wait until the last minute. Get it over with as soon as you can, so when the right moment strikes, you're already focused.

This, BTW, isn't a new technique - it's been pretty much standard practice ever since the introduction of AF 30-some-odd years ago. But of course, not everyone "gets it". My bet is that 95% of complaints about shutter lag on P&S cameras would go away if more people practiced this technique, though.
12-03-2008, 07:38 PM   #30
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QuoteOriginally posted by Marc Sabatella Quote
I'm not sure what you mean by this. The idea is that if you're shooting a portrait, the person presumably isn't moving. So focus once, then shoot as often as you like and don't focus again.
A lot of portrait shooters I know don't adopt the method you've mentioned.
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